Info

"1" I1 S1l "1

Figure 2. The schematic representation of photosynthetic electron transport. The ordinate represents the redox potential of the electron transport chain components, (a) Z-scheme of electron transport in plants, algae, and cyanobacteria. The electron flow from water to NADP + through two photosystems. The chlorophylls P680 and P700 are where light enters the system, raising the redox potential of the respective pigments. On the oxidizing side of PSII are water, the Mn4 cluster and a tyr residue. On the reducing side of PSII are a pheophytin (Pheo) and two quinones (QA and QB). Mediating electron flow from PSII to PSI are the plastoquinone/plastoquinol (PQ/PQH2) pool, the cytochrome b6/f components and plastocyanin (PC). In the cytochrome complex, one electron goes directly to PC, while the other is cycled via cyt b back to the PQ pool (the Q-cycle). On the reducing side of PSI are a monomelic Chi (Ao), a phylloquinone (A,), Fe-S centers and ferredoxin (Fd). Fd-NADP+ reductase (FNR) catalyzes passage of electrons to NADP+. Cyclic electron transport around PSI is connected by the dashed line. The protons consumed in the stroma and generated in the thylakoid lumen form the proton gradient used for ATP synthesis, (b) Photosynthetic electron transport in purple bacteria. There is only one photosystem involved in the electron transport which is analogous to PSII, because of the quinone type of electron carriers involved, (c) Photosynthetic electron transport in heliobacteria. Only one photosystem is involved in the electron transport that resembles the PSI, because of the iron-sulfur and ferrodoxins involved in the electron transport.

Was this article helpful?

0 0
Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

Get My Free Ebook


Post a comment